Eretmocerus eremicus is a tiny parasitic wasp (~1 mm in length) that is indigenous to the southern desert areas of California and Arizona (Rose and Zolnerowich, 1997) and is an important parasitoid of whiteflies. Appearance Female E. eremicus are pale lemon yellow with green eyes and clubbed antennae. The name Eretmocerus is derived from Latin, meaning "oar-like," and refers to the shape of the female antennae. Male wasps have longer, elbowed antennae, and are yellowish brown in color. Whitefly pupae that have been parasitized by E. eremicus appear beige in color whereas healthy whitefly pupae are white or pale yellow. This aphelinid parasitoid does not deposit fecal-like material within the host before emergence as do some other parasitoids of whiteflies. E. eremicus can only emerge through the upper surface of the host. This is accomplished by chewing a circular exit hole. Life Cycle Both male and female E. eremicus develop as primary parasitoids of whiteflies. E. eremicus females locate whitefly hosts, in part, by olfaction. Females lay their eggs between the whitefly nymph and the leaf surface. Females will oviposit under all immature whitefly stages, except eggs, but second instars may be preferred. The E. eremicus egg hatches about 4 days after being laid (the exact time is dependent on temperature) and the wasp larva develops as an external-internal parasitoid. The newly emerged larva attaches its hook-like mouthparts to the underside of the whitefly nymph and chews a small hole into the whitefly. After 3-4 days of chewing the parasitoid larva enters the host where it remains dormant until the whitefly pupates. Once the whitefly pupal stage is reached, the wasp larva releases digestive enzymes, and begins ingesting the semi-liquid body parts of the pupa. The wasp larva passes through three instars, requiring about 12 days to complete development. The adult wasp chews its way out of the whitefly cadaver. Adult female wasps can live for 6-12 days at 27°C. Longevity depends on temperature and availability of food, such as honeydew produced by whiteflies. Females lay 3-5 eggs per day. Female wasps also kill whitefly nymphs by repeatedly probing with their ovipositors and feeding on the haemolymph (blood) that exudes from the wound.